The invention relates to a memory device comprising a domain layer of magnetic material for accommodating a two-dimensional configuration of magnetic domains having a first magnetization direction transverse to said layer, the domain configuration being embedded in a two-dimensional configuration of a background region having a second magnetization direction which is opposite to the first magnetization direction in the domain layer. Such a memory device further comprises generating means, including an input for receiving digital data, for selectively generating, under the control of the data, the two-dimensional configurations of magnetic domains and background region, respectively, and also comprises external bias means for sustaining a bias magnetic field configuration, having a field component transverse to and in the first layer of magnetic material, in order to stabilize the two-dimensional magnetic domain and background region configurations therein. The memory device also comprises detection means for detecting digital data embodied in at least one of the two-dimensional configurations. A device of this kind is known from the article by B. A. Calhoun et al entitled "Column Access of a Bubble Lattice: Column Translation and Lattice Translation", IBM Journal of Research and Development, July 1976, pages 368-375. The known device comprises means for generating an overall, substantially uniform bias magnetic field in a direction transverse to the plane of the plate, for example, by a permanent magnet. A magnet of this kind is usually rather heavy and the invention in this respect aims to provide a memory device based on such magnetic plate materials without requiring a uniform background magnetic field. This results in a device whose weight is lower than that of the known device. Furthermore, in the known device digital data is embodied in the magnetic structure (states) of the walls of the more or less disc-shaped domains. "Hard" as well as "soft" bubble domains occur. Many of the known techniques for the detection of magnetic domains, and hence for the discrimination between the different data contents of the domains, cannot be used in these circumstances, because such techniques detect the presence or absence of the domain walls, not the states thereof. Methods of this kind are based, for example, on the Faraday effect or the magnetoresistance effect. In the device of the above article, discrimination between the various categories of magnetic bubbles can be effected by placing the domain layer in a magnetic field having a gradient. The direction of movement of domains is then dependent of the magnetic structure of the domains' walls. The known memory device, consequently, requires a complex extraction device in which the domains must travel a preselected free path before they are sent into one of two or more detectors under the influence of their different directions of movement.